The overarching therapeutic goal for the UNC tPPG renewal is to clear the hyperconcentrated, adherent mucus that promotes airways obstruction, inflammation, and infection. A straightforward approach to treat muco-obstructive diseases is to rehydrate airway surfaces. However, recent experimental and biophysical analyses have identified that thickened adherent mucus can be modified to generate ?permanent? gels resistant to clearance by hydration. The therapeutic strategy identified to clear permanent mucus gels is the reduction mucin molecular weight (MW). Consequently, the tPPG is configured to take advantage of novel thiol mucin MW reducing agents, e.g., a di-thiol P2176 and a monothiol P2114, and has assembled a full drug development team to quickly and safely bring these molecules into patient populations in need. The tPPG will be overseen by a decision making Project Development/Statistical Core (Core A, Richard C. Boucher, MD, PI) that will guide selection and development of thiol class compounds and oversee selection of drug dose, dosing frequency, drug formulation and clinical trial designs. Projects/Cores overseen include: Project 1 (Michael Rubinstein, PhD., PI: Mechanism of Action of Mucolytics in Improving Mucus Clearance in Lung Disease), will focus on the relative roles of MUC5AC (an ?asthma? mucin) vs. MUC5B (a ?CF/COPD? mucin) as disease specific targets and generate biophysical measurements to assist in compound selection and as biophysical assays for the clinic. Project 2 (Richard C. Boucher, MD, PI: PK/PD Requirements for Mucolytic Therapeutic Agents In Vitro and In Vivo), will utilize in vitro, small animal, and large animal models to compare P2176 with P2114 with respect to mucolytic dose, dosing frequency, and the requirement for a hypertonic saline (HS) formulation. Project 3 (Scott Donaldson, MD, PI: Treatment of Mucostasis and Airways Obstruction in Cystic Fibrosis with a Novel Mucolytic), will test the safety and short term efficacy of P2176/P2114 in CF populations. Project 4 (David Peden, MD, PI: Treatment of Mucostasis and Airways Obstruction in Asthma with a Novel Mucolytic), will test on the safety and short-term efficacy of P2176/P2114 in patients with asthma under basal and allergen challenged conditions. The projects will be supported by three cores: (1) Core B, Analytics for Mucolytics (Mehmet Kesimer, PhD, PI), will provide a broad spectrum of biophysical and biochemical measurements of mucolysis; (2) Core C, In-vivo Imaging of Mucus Obstruction and Clearance (William Bennett, PhD, PI) will provide imaging of subjects, including radio-nuclide mucociliary clearance measurements and F19-MR ventilation imaging; and, (3) Core D, The Pharmacokinetics/Pharmacodynamics (Charles Esther, MD, PhD, PI) will provide measurements of pharmacodynamic and drug pharmacokinetic measurements of thiol compounds. The tPPG deliverable is to mobilize our experienced drug development group to advance a novel class of IND-ready therapeutic compounds into patients in need of pulmonary mucus clearance, including, asthma, CF, ultimately COPD.